There are many approaches to modeling the human. Most of these methods were designed to accomplish specific aims such as easier sculpting of facial features, better facial animation, easier texturing, and so on. Of all these techniques subdivision or subpatch modeling has the scope to achieve all the necessary objectives for modeling a realistic human and its subsequent goals of lifelike movements and facial expressions.

This chapter outlines a method for modeling a human female. If your desire is to model a male, then you can refer to my other book 3D Human Modeling and Animation, 2nd Ed. (John Wiley and Sons Publishers).

Although most of human modeling will be examined in this chapter, the following chapter 7 will cover details such as hair, eyes, teeth, and so on. It is recommended that you work from photographs and also photographic templates that show front, side, back, and perhaps top views of the figure.

In the previous chapter 2 you learned how to model a figure with clothes. This time the human will be undraped so as to make one more aware of human anatomy. During the greatest ages of art, the nude inspired the greatest art works. Even when it no longer held sway over art movements, it still retained its importance in the academic training of artists.

The Greeks in the fifth century taught us that the nude is not just a subject to be studied and imitated but an art form in itself. Their knowledge gave us an understanding of the actions and structural characteristics found in the nude. Artists who painted and sculpted the nude learned to convey weight, rhythm, mass, line, value, texture, and tension.

To be successful in depicting the human body one needs to have an understanding of anatomy. Perceiving the nude means understanding it. Without any knowledge of anatomy, it is impossi- ble to recognize the inherent form of the nude.

Anatomy for the artist does not imply a doctor's understanding of the body. Internal organs, blood vessels, muscles, and bones that are not visible at or below the skin surface are not a concern to the 3D modeler.

The 3D animator should have knowledge of the skeletal/muscular system and the manner in which it works as a mechanical device. Without this understanding it is very difficult to portray the human character in its various attitudes and movements.

There are many excellent books on human anatomy for artists. This book does not pretend to be one of them. The study of anatomy requires an entire book devoted to the subject. Anyone who is serious about studying 3D human modeling and animation should have a collection of anatomy books.

The various steps in this chapter that describe the manner in which to model the figure also contain some illustrations of human anatomy. These pertain to the specific modeling task at hand. The anatomy illustrations are only meant as a visual guide to help you see what lies below the surface of the part that will be modeled. They do not identify their individual anatomical details with medical names. If you wish to know the designations of different bones and muscles, they can be found in anatomy textbooks or online.

Even though males and females have their differences, they are structurally homological to each other. Fat deposits and variations in their skeletons account for the greatest deviations.

The greater quantity of fat in the female makes her appear smooth and flowing. Aside from sexual differences, she is normally smaller except in the hips.

The difference in the skeletal structure makes the female slighter in proportion. Her head is smaller and positioned relatively higher than the male. The brow ridges, unlike the male are nearly absent adding to the forehead's smoother and more rounded appearance. The width of the shoulders to that of the trunk is smaller. In fact, it is the opposite to the male whose shoulders are wider than the hips. The thyroid cartilage (Adam's Apple) is flat compared to the prominent one in the male.

The trunk of the female in contrast to the male has a shorter rib cage with the outwardly visible breasts. The female pelvis is shorter but wider and deeper and leans forward. At the base of the spine, the sacrum is broader and inclines behind to form a full triangle. The two dimples of this triangle are clearly visible. Due to a wider pelvis and fat deposits, the female is broader at the hips. The side between the ribs and hipbone is longer owing to the female's shorter rib cage and pelvis. The buttocks extend to a lower level than the male. The female also has a smoother more rounded abdomen with a deeper navel.

The female upper arm is shorter resulting in a higher location of the elbow. When the arms are resting at the sides of the body, the finger tips extend to a higher point at the thigh. The wrist and hand are smaller.

The wider hipbones separate the legs in their pelvic sockets to a greater degree. This makes the legs slant more toward the knees. The knees are fleshier but the kneecaps and their ligaments are less obvious. The calves located below the knees are lower on the female. The feet are smaller.

Artists throughout the ages have tried to calculate the average size of a human. Despite all that, we still do not know the normal scale of the figure. Classic Greek and Renaissance bodies were 8 heads tall. Mannerists such as El Greco and Pontormo painted long figures measuring 9 heads or more.

The French anatomist Richer was the first to formulate that the traditional measurement of the average human was about seven and one-half skull-lengths. Although in real life a figure of that height would seem well proportioned, on a 2D sur- face the body appears much broader and stockier. To remedy this, artists have found that when portraying the nude as 8 heads tall, the figure appears more slender and graceful.

One of the more difficult tasks for computer artists is to model objects in the right proportions. Therefore, in order to simplify your work and help you model more accurately, it is recommended that you take digital pictures of a nude figure. It is also advisable to take close-up views of the head, hands, and feet. Perhaps someone will create an online repository of assorted nude figures in their various poses. As more artists contribute to the site, these should serve as an invaluable aid to 3D modelers.

Modeling the Head

Before starting to model the face, it is recommended that you study the various muscles and their purpose. While reading about these muscles, you may want to use a hand-held mirror to observe their effects on various expressions.

The Skull

Since the muscles of the head are thin and flat, it is the shape of the skull that dictates the overall form of the head. Figure 6-1 illustrates various views of the skull. Visualizing the skull beneath the head makes it easier to see their respective masses that shape the face.

Fig. 6-1 Some of the more prominent features of the skull that affect the contours of the face are the forehead, eye sockets, nasal bone, cheekbones, the empty pockets between the jaw and cheekbones, and the chin.

The Muscles of the Head

Fig. 6-2 The muscles of the head are divided into three groups: scalp, face, and mastication.

It is important to note that no skeletal muscle acts on its own. When one muscle contracts or draws together its fibers, it activates other, opposing muscles, which in turn, modify the action of the original contracting muscle. Normally, the head is broken up into three sets of muscles. Most of these are small, thin, or deeply embedded in fatty tissue. A few of the muscles shown in Figure 6-2 warrant special attention. They play an important role in facial expressions and help define the contours of the face.